The Effect of Ti Content in the Filler Powder on Interfacial Microstructure and Mechanical Properties of C/C Composites/T2-Copper Joints via Thermo-Compensated Resistance Brazing Welding

Abstract

The carbon/carbon (C/C) composites and T2-copper were joined via thermo-compensated resistance brazing welding (RBW) with AgCuTi filler powder. The effects of the Ti content in AgCuTi filler powder on the interfacial microstructure and mechanical properties of resistance brazed joints were discussed in detail. The experiment results indicated that the interface structure of welded joints with composite filler metal was C/C composites/(TiC + TiCu) intermetallic compounds/Cu(s,s)/T2-copper. TiC and Ti-Cu were likely generated at the interface according to thermodynamics. When Ti content in the composite filler metal was 6 wt.%, the thickness of the reaction layer at the interface reached 4.2 μm, and the maximum shear strength of the joints reached 14.68 Mpa, which was the largest compared to other Ti contents. The EDS and XRD results of the fracture surfaces indicated that the TiCu and TiC IMCs were generated at the interface. Combined with the fracture morphologies, the fracture partially occurred in the TiC + TiCu layer, and partially occurred in the base metal of the C/C composites and the Cu alloy.